The present invention relates to refrigerating or condensing units of the type commonly utilized in refrigeration appliances, and particularly to means for mounting the heat exchanger or condenser on the base of the refrigerating unit and shrouds for directing airflow through the heat exchanger and improving the efficiency of the heat exchange.
Previous condensing units typically included condensers which were mounted via brackets directly to the base of the condensing or a vertical frame fixed to or formed on the base. These brackets are typically attached to the condenser's headers or heat exchange tubes.
An electric fan is usually provided to pull ambient air through the heat exchanger, the airflow generated by the fan being directed by a shroud which substantially encloses the downstream side of the condenser but is provided with a large round aperture, the edge of which is in close proximity to the radially-outermost edges of the fan blades. The shroud may be made of heavy paper or cardboard, metal, or plastic, and is typically attached to heat exchanger headers or heat exchange tubes using brackets. An example of such a shroud is shown in FIG. 1. Shroud 10 is made of sheet metal or cardboard folded into a four-sided substantially parallelepiped shape having top 12, sides 14 and 16 and rear panel 18. Panel 18 is provided with round aperture 20 in which the blades of a motor-driven fan (not shown) are disposed. Near the free edges of sides 14 are 16, a plurality of holes 22 are provided. Holes 22 accommodate screws (not shown) by which shroud 10 is secured via brackets attached to vertically-extending headers provided on opposite edges of the condenser. Shroud 10 is thus attached to a condenser which is separately fixed to the condensing unit base as described above. Notably, it is also common in the prior art for the above-mentioned motor-driven fan to be attached to panel 18 of shroud 10, thereby necessitating their disassembly should one component need to be replaced, and removal of both the shroud and fan from the condensing unit should the condenser, to which both are attached, need to be replaced.
Refrigerant flows to and from the heat exchanger through inlet and outlet tubes typically located near one end of one or both headers. Some previous shrouds require that holes or notches be provided therein through which the condenser inlet and outlet tubes extend, these holes or notches perhaps being added during the assembly process and being uniquely placed depending on the various locations of the inlet and outlet tubes among different condensers. Further, these holes or notches in the shroud may allow air leakage therethrough, which can compromise heat exchanger performance due to ambient air being recirculated through the shroud, rather than directed through the heat exchanger.
Heat exchangers for condensing units have evolved to a preferred design having a pair of vertically-oriented, cylindrical headers, the ends of which are closed, and between which extend a plurality of flat, horizontal heat exchange tubes within each of which are formed a plurality of microchannels. Refrigerant flows between the headers through the microchannels. The heat exchange tubes extend through, and are in contact with, a plurality of vertically-oriented flat fins. Heat is transferred convectively from the refrigerant flowing through the microchannels to the heat exchange tubes, conductively from the heat exchange tubes to the fins, and convectively from the fins to the ambient air flowing through the heat exchanger. Refrigerant enters and exits the heat exchanger through inlet and outlet tubes which are located near opposite ends of one cylindrical header, or near one end of each header, these locations usually being determined by package and performance considerations. Some previous shrouds require that holes or notches be provided therein through which the condenser inlet and outlet tubes extend, these holes or notches perhaps being added during the assembly process and being uniquely placed depending on the various locations of the inlet and outlet tubes among different condensers. Further, these holes or notches in the shroud may allow air leakage therethrough, which can compromise heat exchanger performance due to ambient air being recirculated through the shroud, rather than directed through the heat exchanger.
Heat exchangers having cylindrical headers are known in the art, and are disclosed in, for example, U.S. Pat. No. 4,936,381 (Alley); U.S. Pat. No. 5,320,165 (Hughes); U.S. Pat. No. 5,372,188 (Dudley et al.); U.S. Pat. No. 6,360,818 (Bosch et al.); and U.S. Pat. No. 5,947,196 (Halm et al.); and in Halm's published U.S. patent applications Ser. Nos. 09/370,405 and 09/759,930.
The cylindrical headers and the flat tubes of the now-preferred condenser designs do not lend themselves well to the above-described means for attachment of the condenser to the condensing unit base, or the shroud to the condenser. Thus, an improved mounting means for condensers having cylindrical headers is desired. It is also desired that such an improved condenser mounting means employ relatively fewer parts and tools, and require less condensing unit assembly time. Further, it would be desirable that the condenser and motor-driven fan be separably removable from the condensing unit, thereby facilitating fast and easy repair of the condensing unit.
Moreover, it is desirable to provide a common shroud which can accommodate condensers having various condenser inlet and outlet tube locations, and which is provided with features which facilitate more efficient techniques for assembly of the condenser and shroud, and of the condensing unit as a whole.